Folding apparatus in which a folding blade is carried by a folding blade cylinder to cooperate with a folding gripper cylinder are known and described in the literature, see for example "Atlas des Zeitungs- und Illustrationsdruckes", FIG. 85 ("Atlas of Newspaper and Magazine Printing", see FIG. 85). Folding apparatus of the type described therein are capable of folding a plurality of superposed printed sheets for common transverse folding. A folding blade secured to the folding blade cylinder presses into the uppermost one of the printed sheets along a predetermined transverse fold line to press the sheets into a groove or notch of a fold gripper cylinder, so that the folded sheets can be gripped therein. Upon return of the folding knife, the next adjacent, then innermost sheet might separate from the outer sheets adjacent thereto and follow, at least in part, the return path of the folding blade. Such inadvertent movement of the innermost sheet together with the folding blade substantially interferes with continuous high-speed production.